a Université de Strasbourg, CNRS, IBMP UPR , Strasbourg , France.
RNA Biol. 2017 Dec 2;14(12):1637-1641. doi: 10.1080/15476286.2017.1343787. Epub 2017 Jul 31.
Double-stranded RNA binding (DRB) proteins are generally considered as promoting cofactors of Dicer or Dicer-like (DCL) proteins that ensure efficient and precise production of small RNAs, the sequence-specificity guide of RNA silencing processes in both plants and animals. However, the characterization of a new clade of DRB proteins in Arabidopsis has recently challenged this view by showing that DRBs can also act as potent inhibitors of DCL processing. This is achieved through sequestration of a specific class of small RNA precursors, the endogenous inverted-repeat (endoIR) dsRNAs, thereby selectively preventing production of their associated small RNAs, the endoIR-siRNAs. Here, we concisely summarize the main findings obtained from the characterization of these new DRB proteins and discuss how the existence of such complexes can support a potential, yet still elusive, biological function of plant endoIR-siRNAs.
双链 RNA 结合（DRB）蛋白通常被认为是促进 Dicer 或 Dicer 样（DCL）蛋白的辅助因子，它们确保了小 RNA 的高效和精确产生，这是动植物中 RNA 沉默过程的序列特异性指南。然而，最近拟南芥中新的 DRB 蛋白簇的特征表明，DRB 也可以作为 DCL 加工的有效抑制剂。这是通过隔离特定类别的小 RNA 前体，即内源性反向重复（endoIR）dsRNA 来实现的，从而选择性地阻止其相关小 RNA，即 endoIR-siRNAs 的产生。在这里，我们简要总结了从这些新的 DRB 蛋白的特性研究中获得的主要发现，并讨论了这些复合物的存在如何支持植物 endoIR-siRNA 的潜在但仍难以捉摸的生物学功能。
